mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-22 07:32:48 +00:00
51a0280d29
A common idiom is to use zero and all-ones as sentinal values and to
check for both in a single conditional ("x != 0 && x != (unsigned)-1").
That generates code, for i32, like:
testl %edi, %edi
setne %al
cmpl $-1, %edi
setne %cl
andb %al, %cl
With this transform, we generate the simpler:
incl %edi
cmpl $1, %edi
seta %al
Similar improvements for other integer sizes and on other platforms. In
general, combining the two setcc instructions into one is better.
rdar://14689217
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188315 91177308-0d34-0410-b5e6-96231b3b80d8
15 lines
408 B
LLVM
15 lines
408 B
LLVM
; RUN: llc < %s -mcpu=cortex-a8 -march=arm -asm-verbose=false | FileCheck %s
|
|
|
|
define zeroext i1 @test0(i32 %x) nounwind {
|
|
; CHECK-LABEL: test0:
|
|
; CHECK-NEXT: add [[REG:(r[0-9]+)|(lr)]], r0, #1
|
|
; CHECK-NEXT: mov r0, #0
|
|
; CHECK-NEXT: cmp [[REG]], #1
|
|
; CHECK-NEXT: movhi r0, #1
|
|
; CHECK-NEXT: bx lr
|
|
%cmp1 = icmp ne i32 %x, -1
|
|
%not.cmp = icmp ne i32 %x, 0
|
|
%.cmp1 = and i1 %cmp1, %not.cmp
|
|
ret i1 %.cmp1
|
|
}
|